What are the effects of chlorpromazine?

From the Guidelines

Chlorpromazine has significant effects on the body, including sedation, antiemetic properties, and reduction of psychotic symptoms, but it also carries risks of extrapyramidal symptoms, orthostatic hypotension, and metabolic effects, as noted in the 2018 ESMO clinical practice guidelines for delirium in adult cancer patients 1.

Key Effects of Chlorpromazine

• Sedating and anticholinergic effects
• May cause extrapyramidal symptoms (EPSEs) and orthostatic hypotension
• Can prolong QTc interval
• Recommended starting dose is 12.5–25 mg p.o. or p.r. stat, with scheduled dosing required at intervals of q6h–q12h
• Use with caution in patients with renal and hepatic impairment

Considerations for Use

• Chlorpromazine is a first-generation antipsychotic, and its use should be carefully considered due to the potential for significant side effects
• The medication can be given orally, parenterally, or via slow intravenous infusion, but parenteral use may cause local irritation
• In older patients, doses should be started in the lower range due to increased sensitivity to side effects
• Monitoring for QTc interval prolongation and extrapyramidal symptoms is essential, especially in patients with risk factors for these conditions

Clinical Decision Making

• The decision to use chlorpromazine should be based on a thorough assessment of the patient's condition, weighing the potential benefits against the risks of side effects, as guided by the most recent clinical practice guidelines 1.
• Alternative antipsychotic medications, such as second-generation antipsychotics, may be considered to minimize the risk of extrapyramidal symptoms and other side effects
• Close monitoring and regular follow-up are crucial to adjust the treatment plan as needed and minimize adverse effects.

From the FDA Drug Label

Chlorpromazine has actions at all levels of the central nervous system – primarily at subcortical levels – as well as on multiple organ systems. The principal pharmacological actions are psychotropic. It also exerts sedative and antiemetic activity. Chlorpromazine has strong antiadrenergic and weaker peripheral anticholinergic activity; ganglionic blocking action is relatively slight. It also possesses slight antihistaminic and antiserotonin activity. The effects of chlorpromazine include:

• Psychotropic effects: altering mental activity and behavior
• Sedative effects: producing a calming or sleep-inducing effect
• Antiemetic effects: preventing or alleviating nausea and vomiting
• Antiadrenergic effects: blocking the action of adrenaline (epinephrine) in the body
• Anticholinergic effects: blocking the action of the neurotransmitter acetylcholine in the body
• Antihistaminic effects: blocking the action of histamine in the body
• Antiserotonin effects: blocking the action of serotonin in the body 2

From the Research

Effects of Chlorpromazine

• Chlorpromazine is a typical antipsychotic drug that has been widely used for the treatment of schizophrenia 3, 4.
• It has been shown to be effective in promoting global improvement in patients with schizophrenia, although it can cause significant adverse effects such as sedation, extrapyramidal symptoms, and low blood pressure 4.
• Compared to atypical antipsychotic drugs, chlorpromazine may have a higher risk of extrapyramidal symptoms, but its efficacy is similar to that of some atypical antipsychotics such as risperidone and quetiapine 3.
• The optimal dose of chlorpromazine is still unclear, but lower doses (≤ 400 mg/day) may be associated with fewer extrapyramidal symptoms and similar efficacy compared to higher doses 5.
• Chlorpromazine can cause significant metabolic and cardiac adverse effects, particularly at high doses, and clinicians should weigh the risk-benefit ratio for each patient 6.

Comparison with Other Antipsychotics

• Chlorpromazine has been compared to atypical antipsychotics such as olanzapine, risperidone, and quetiapine, and its efficacy is similar to that of some of these drugs 3.
• Clozapine, an atypical antipsychotic, has been shown to be well tolerated and therapeutically superior to chlorpromazine in treating psychotic behavior, particularly in patients with tardive dyskinesia or other extrapyramidal side effects 7.
• The choice of antipsychotic medication should be based on the individual patient's needs and risk factors, and clinicians should consider the potential benefits and risks of each medication 6.

Adverse Effects

• Chlorpromazine can cause significant adverse effects, including extrapyramidal symptoms, sedation, low blood pressure, and metabolic and cardiac effects 3, 4, 6.
• The risk of adverse effects can be minimized by using lower doses and monitoring patients regularly for signs of adverse effects 5, 6.
• Clinicians should be aware of the potential risks and benefits of chlorpromazine and other antipsychotic medications, and should make informed decisions based on the individual patient's needs and risk factors 6.